Per-calendar watch channels with a per-channel secret, renewed before their roughly seven-day expiry. A webhook verifies the channel and its token, ignores the initial handshake ping, and syncs that person. Channels for calendars the person un-ticks are stopped and removed. Disconnecting stops every channel.
Also called: push notifications · instant calendar sync · watch channel · live updates
- 1ensureWatch creates a channel per synced calendar with a random secret and an expiry.
- 2Google posts to the webhook on any change, with no body.
- 3The webhook resolves the channel to a user and verifies the secret.
- 4The first 'sync' state is a handshake and is ignored.
- 5Anything else triggers an immediate sync; the response is always 200 so Google does not retry-storm.
- 6Channels within a day of expiry are renewed and the old one stopped.
Documented as Keith 08-19 on the webhook, with the operational constraint recorded in the sync module: 'Google caps Calendar channels at ~7 days; renew when < 1 day left.' The always-200 rule is stated as a deliberate protection against retry storms.
- Calendar changes were only picked up on the next scheduled sync.
- Expiring channels silently stopped delivering updates.
See it on your own jobs
Twenty minutes, your numbers, no slide deck. We’ll build one of your real buildings in front of you and send you the estimate link at the end — yours to keep either way.
or keep browsing features →